Heat exchanger and related method of manufacture

ABSTRACT

A heat exchanger for an internal combustion engine of a motor include first and second radiator tanks and a plurality of radiator tubes extending between the first and second radiator tanks. The first radiator tank includes a plurality of walls. Brazed joints are between the plurality of walls to make the first radiator tank liquid tight. Brazed joints are also between the plurality of radiator tubes and the first and second radiator tanks. An oil-cooling structure is disposed inside the first radiator tank. The brazed joints between the plurality of walls and between the plurality of radiator tubes and the first and second radiator tanks are simultaneously formed.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. provisional application Ser. No. 61/197,268, filed on 27 Oct. 2008, which is incorporated by reference as if fully set forth herein.

FIELD

The present teachings generally relate to a heat exchanger for an internal combustion engine of a motor.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

Radiators are conventionally used in motor vehicles for cooling of internal combustion engines. An exemplary cooling radiator for a motor vehicle is illustrated in FIGS. 1 and 2 and generally identified at reference character 1. The radiator 1 is illustrated to generally include a pair of headers 2 and a plurality of tubes 3 extending between the headers 2. The tubes 3 are inserted into the headers 2 and brazed to the headers 2 to prevents leakage. Coolant circulates through the plurality of tubes 3. Plastic tanks 4 are mounted to the headers 2. As illustrated, an edge 5 of the headers 2 may be rolled over a flange 6 of the tanks 4 for securing the tanks 4 to the headers 2. A gasket 8 may be placed between the headers 2 and the associated tank 4 to prevent leakage.

Coolant may be circulated through the tubes 3. As the tubes 3 are exposed to the atmosphere, heat may be released from the coolant in this manner. Cooling fins (not shown) may be located between the radiator tubes 3. The fins may increase the total heat exchange area between the radiator 1 and the atmosphere.

As further illustrated, a transmission oil cooler 9 may be conventionally placed inside one of the radiator tanks 4. The transmission oil cooler 9 may include a plurality of tubes 10 for circulating circulate hot transmission fluid between an oil inlet tank 11 having an oil inlet 11A and an oil outlet tank 12 having an oil outlet 12A. The transmission oil cooler 9 is immersed into the coolant that fills the radiator tank 4. The oil is cooled because even though the coolant is also hot, its temperature is significantly lower than the oil temperature. The temperature differential is used to transfer heat from the oil to the coolant, and ultimately to the atmosphere.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

In accordance with one particular form, the present teachings provide a heat exchanger for an internal combustion engine of a motor. The heat exchanger includes first and second radiator tanks and a plurality of radiator tubes extending between the first and second radiator tanks. The first radiator tank includes a plurality of walls. Brazed joints are between the plurality of walls to make the first radiator tank liquid tight. Brazed joints are also between the plurality of radiator tubes and the first and second radiator tanks. An oil-cooling structure is disposed in the first radiator tank. The brazed joints between the plurality of walls and between the plurality of radiator tubes and the first and second radiator tanks are simultaneously formed.

In accordance with another particular form, the present teachings provide a heat exchanger for an internal combustion engine of a motor. The heat exchanger includes a first radiator tank, a second radiator tank and a plurality of aluminum radiator tubes. The first radiator tank includes a plurality of aluminum walls brazed together to define a liquid-tight structure. The first radiator tank defines an oil inlet chamber, an oil outlet chamber and a coolant chamber therebetween. The second radiator tank constructed of aluminum. An oil-cooling structure is disposed in the first radiator tank. The plurality of aluminum radiator tubes are brazed to the first and second radiator tanks provide fluid communication between the coolant chamber and the second radiator tank.

In accordance with yet another particular form, the present teachings provide a method of manufacturing a heat exchanger for an internal combustion engine of a motor. The method includes providing a first radiator tank including a plurality of aluminum panels and providing a second radiator tank constructed of aluminum. The method additionally includes providing a plurality of aluminum radiator tubes. The method further includes brazing the heat exchanger to simultaneously joint the plurality of aluminum panels of the first radiator tank in a fluid-tight manner and join the plurality of radiator tubes to both the first and second radiator tanks.

In accordance with still yet another form, the present teachings provide a heat exchanger for an internal combustion engine of a motor including a first radiator tank, an oil-cooling structure and a plurality of aluminum radiator tubes. The first radiator tank includes a plurality of aluminum walls brazed together to define a liquid-tight structure. The first radiator tank defines an oil inlet chamber, an oil outlet chamber and a coolant chamber therebetween. A first wall of the plurality of aluminum walls is disposed between the oil inlet chamber and the coolant chamber and a second wall of the plurality of aluminum walls is disposed between the oil outlet chamber and the coolant chamber. An oil-cooling structure is disposed in the first radiator tank. The oil-cooling structure includes a plurality of convoluted tubes disposed in the coolant chamber and extending between the oil inlet chamber and the oil outlet chamber. Brazed joints secure the plurality of convoluted tubes to the first and second walls of the plurality of aluminum walls. The plurality of aluminum radiator tubes are brazed to the first and second radiator tanks and provide fluid communication between the coolant chamber and the second radiator tank.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure:

FIG. 1 is a sectional view of a prior art cooling radiator;

FIG. 2 is another sectional view of the prior art cooling radiator of FIG. 1;

FIG. 3 is a side view shown in partial cross section of a heat exchanger constructed in accordance with the present teachings;

FIG. 4 is another view of the heat exchanger of FIG. 3 shown in partial cross section;

FIG. 5 is a schematic view of another heat exchanger in accordance with the present teachings, the heat exchanger illustrated to include a bi-metal oil valve and a bi-metal coolant valve, the bi-metal oil valve illustrated in an open position, the bi-metal coolant valve shown in a closed position or condition;

FIG. 6 is a cross-sectional view of a portion of FIG. 5, the bi-metal coolant valve shown in the closed position;

FIG. 7 is an enlarged view of a portion of the schematic view of FIG. 5, the oil valve shown in a closed position or condition;

FIG. 8 is a view similar to FIG. 6, illustrating the coolant valve in an open position or condition;

FIG. 9 is a schematic view of another heat exchanger in accordance with the present teachings with an electronically-controlled oil valve and an electronically-controlled coolant valve, the oil valve shown in a cold oil or open condition and the coolant valve shown in a cold coolant or closed condition;

FIG. 10 is an enlarged view of a portion of FIG. 9;

FIG. 11 is a view similar to FIG. 10, the coolant valve shown in an open condition;

FIG. 12 is an enlarged view of a portion of FIG. 9, the oil valve shown in a hot oil or closed condition;

FIG. 13 is a schematic view of another heat exchanger in accordance with the present teachings, the heat exchanger including a wax element coolant valve and a wax element oil valve, the oil valve shown in an open or cold condition, the coolant valve shown in a closed or cold condition;

FIG. 14 is an enlarged view of a portion of FIG. 13, the coolant valve shown in a hot coolant or open condition; and

FIG. 15 is another enlarged view of a portion of FIG. 13, the oil valve shown in a hot oil or closed condition.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. To the extent not otherwise described, it will be understood that the elements throughout the various views are drawn to scale.

DESCRIPTION OF VARIOUS ASPECTS

Exemplary embodiments consistent with the present teachings will now be described more fully with reference to the accompanying drawings.

With initial reference to FIGS. 3 and 4, a radiator in accordance with the present teachings is illustrated and identified at references character 20. The radiator 20 is illustrated to generally include a first or upper tank 22 and a second or lower tank 24. A plurality of tubes 26 extends between the upper tank 22 and the lower tank 24. Cooling fins (not illustrated) may be located between the radiator tubes 26. The fins may increase the total heat exchange area between the radiator and the atmosphere.

The upper tank 22 may have a closed shape. The closed shape may be rectangular, circular or any other suitable shape. The upper tank 22 may include a plurality of metal panels. In one particular application, the metal panels may be constructed of aluminum. As used herein, the term aluminum will be understood to include aluminum alloy. Those skilled in the art will appreciated that various of the present teachings are not limited to any particular material.

The upper tank 22 may include a main panel 28. As shown in the side view of FIG. 4, the main panel 28 may be generally U-shaped. The upper tank may additionally include a lower panel 30 and a pair of end caps 32A and 32B. The upper tank 22 may further include a pair of internal panels 34A and 34B. The lower panel 30 may serve as an integral header thereby eliminating the need for a discrete header. The lower panel 30 may be formed to include a plurality of openings or slots punched therein for receiving the plurality of tubes 26.

The various panels of the upper tank 22 may cooperate to define distinct chambers. In this regard, an oil inlet chamber 36 having an oil inlet 36A is defined between the end cap 32A and the internal panel 34A. An oil outlet chamber 37 having an oil outlet 37A defined between the end cap 32B and the internal panel 34B. A coolant chamber 40 is defined between the internal panels 34A and 34B.

A plurality of oil-cooling tubes 38 may extend between the internal panels 34A and 34B. The internal panels 34A and 34B may include a plurality of openings or slots punched therein for receiving the plurality of oil-cooling tubes 38. The oil-cooling tubes 38 may be straight, convoluted, dimpled, internally equipped with turbulators or shaped in any other form that stirs the oil and forces it to frequently change direction, in order to increase heat exchange.

The lower tank 24 may be formed similar to the upper tank 22 to include a main panel that may be generally U-shaped and a pair of end caps 42A and 42B. The lower tank 24 may further include an upper panel 44. The upper panel 44 may serve as an integral header thereby eliminating the need for a discrete header. The upper panel 44 may be formed to include a plurality of openings or slots punched therein for receiving the plurality of tubes 26.

The radiator 20 may be brazed to define a liquid-tight relationship between the plurality of tubes 26 and the upper and lower tanks 22 and 24. The brazing may additionally define a liquidtight relationship between the plurality of oil-cooling tubes 38 and the internal panels 34A and 34B. Furthermore, the brazing may define a liquid-tight relationship between the various metal panels of the respective tanks 22 and 24.

The water chamber 40 may be filled with coolant in the form of water or other suitable fluid. As such, the plurality of oil-cooling tubes 38 may be immersed in water. When hot oil is circulated in the oil-cooling tubes 38, heat may be extracted from the tubes 38.

The present teachings dramatically simplify the manufacturing process for radiators as the radiator 20 may now be assembled in one piece and brazed a single time. A separate oil cooler found with conventional radiators may be eliminated since the oil-cooling tubes located inside the tank provide a corresponding function. Furthermore, conventional plastic tanks may be eliminated along with the gaskets conventionally located between headers and radiator tanks. Discrete radiator headers are also eliminated. The gaskets between the oil fittings and the radiator tank walls are eliminated, because the fittings are now integral with and securely brazed to the radiator. The present teachings may generates significant cost savings as a result of the more simple manufacturing process and may provide a significant increase in reliability through elimination of leak paths. In this regard, the traditional leak path between the radiator tank and the radiator header is eliminated.

Turning to FIGS. 5 through 8, a heat exchanger constructed in accordance with the present teachings is illustrated and generally identified at reference character 100. As will be described further below, the heat exchanger 100 incorporates a coolant flow control and an oil flow control. It will be understand that elements similar to the embodiment of FIGS. 3 and 4 may be similarly constructed and manufactured. Given the various similarities between the two embodiments, like reference characters will be used to identify similar elements. Cooling fins (not illustrated) may be located between the radiator tubes 26. The fins may increase the total heat exchange area between the radiator and the atmosphere.

The first tank 102 may have a closed shape. The closed shape may be rectangular, circular or any other suitable shape. The first tank 102 may include a plurality of metal panels. In one particular application, the metal panels may be constructed of aluminum. Again, those skilled in the art will appreciated that various of the present teachings are not limited to any particular material.

The first tank 102 may include a main panel 106. As with the earlier described embodiment, the main panel 106 may be generally U-shaped. The first tank 102 may additionally include a panel 108 with slots punched therein for receiving the plurality of tubes 26. The main panel 106 may define a coolant outlet 106A.

The first tank 102 may include internal panels and end caps similar to the previously described embodiment. As alternatively illustrated, the first tank 102 may include may include an oil inlet tank 110 defining an oil inlet 110A and an oil outlet tank 112 defining an oil outlet 112A. The upper tank 22 may further include a pair of end caps 32A and 32B, and a pair of internal panels 34A and 34B. The lower panel 30 may serve as an integral header thereby eliminating the need for a discrete header. The lower panel 30 may be formed to include a plurality of openings or slots punched therein for receiving the plurality of tubes 26.

A plurality of oil-cooling tubes 38 may extend between the oil inlet tank 110 and the oil outlet tank 112. The oil inlet tank 110 and the oil outlet tank 112 may include a plurality of openings or slots punched therein for receiving the plurality of oil-cooling tubes 38. The oil-cooling tubes 38 may be straight, convoluted, dimpled, internally equipped with turbulators or shaped in any other form that stirs the oil and forces it to frequently change direction, in order to increase heat exchange. The oil-cooling tubes 38 may be brazed to the panels 34A and 34B.

The second tank 104 may be formed similar to the lower tank 24 to include a main panel 40 that may be generally U-shaped and a pair of end caps 42A and 42B. The second tank 104 may further include a panel 44. The upper panel 44 may serve as an integral header thereby eliminating the need for a discrete header. The upper panel 44 may be formed to include a plurality of openings or slots punched therein for receiving the plurality of tubes 26.

The heat exchanger 100 may be brazed to define a liquid-tight relationship between the plurality of tubes 26 and the first and second tanks 102 and 104. The brazing may additionally define a liquid-tight relationship between the plurality of oil-cooling tubes 38 and the oil inlet and outlet tanks 110 and 112. Furthermore, the brazing may define a liquid-tight relationship between the various metal panels of the respective tanks 102 and 104.

A coolant chamber 40 defined between the oil inlet and outlet tanks 110 and 112 may be filled with coolant in the form of water or other suitable fluid. As such, the plurality of oil-cooling tubes 38 may be immersed in coolant. When hot oil is circulated in the oil-cooling tubes 38, heat may be extracted from the tubes 38.

The heat exchanger may further include a bypass arrangement for selectively providing additional fluid communication between the oil inlet tank 110 and the oil outlet tank 112. This fluid communication may be in addition to the fluid communication constantly provided by the plurality of oil-cooling tubes 38. The bypass arrangement provides for the additional fluid communication between the oil inlet and outlet tanks 110 and 112 under a first operating condition and precludes or blocks the additional fluid communication between the oil inlet and outlet tanks 110 and 112 under a second operating condition. The first and second operating conditions may be dependent on the temperature of the oil in the oil inlet tank 110.

The bypass arrangement may include a bypass tube 120 in fluid communication with the oil inlet and outlet tanks 110 and 112 and means for selectively blocking the bypass tube 120. As illustrated, the heat exchanger 100 10 includes a single bypass tube 120. In other applications, the heat exchanger 100 may include 2 or more bypass tubes 120 within the scope of the present invention. The bypass tube 120 may be brazed or otherwise suitably attached to the oil inlet and outlet tanks 110 and 112. In one application, the cross section of the bypass tube 120 may be elliptical in shape. Alternatively, the cross section of the bypass tube 120 may be oval, rectangular, round or any other desired shape.

The means for selectively blocking the bypass tube 120 may be automatically responsive for blocking the bypass tube in response to a predetermined condition. This predetermined condition may be reached upon a predetermined temperature of the oil in the oil inlet tank 110. For example, the means for automatically blocking the bypass tube may be responsive to block the bypass tube 120 upon a predetermined oil temperature within the oil inlet tank 110. This predetermined temperature may be approximately 160 degrees Fahrenheit or any other identified temperature.

The means for selectively blocking the bypass tube 120 may include a temperature-responsive valve 124. The temperature-responsive valve 124 may include an element 126 movable between a first position and a second position in response to a change in temperature. The temperature-responsive element 126 may be generally U-shaped, having a first or fixed end secured to the tank 110 and a second or free end movable relative to the tube 120. The first position of the element 126 is shown in FIG. 5. In this first position, the element 126 is spaced from the bypass tube 120 and allows for the flow of oil between the oil inlet tank 110 and the oil outlet tank 112. The second position is shown in FIG. 7 and operates to prevent oil from passing through the bypass tube 120. One suitable U-shaped bi-metal element is shown and described in common assigned U.S. Publication No. 2009/0114,183, which is incorporated by reference as if fully set forth herein.

The element 126 of the temperature-responsive valve 124 may be a bi-metal element 126. The bi-metal element 126 may be a U-shaped strip. The bi-metal element 126 may be disposed in the oil inlet tank 110 and secured to the oil inlet tank 110 with a bracket (not shown). Attachment of the element 126 to the bracket may be accomplished with rivets or other suitable means, including but not limited to brazing. When the inlet oil temperature is below the predetermined temperature, the bi-metal element 126 is in the first position. Because the bypass arrangement 120 controls the maximum oil pressure of the heat exchanger 100, conventional hoses and fittings do not need to be as heavy. When most of the oil flow is through the bypass tube 120 rather than the heat exchange tubes 38, the oil temperature rises to an optimum operating temperature more quickly. In this manner, the disadvantages of cold starts are overcome.

When the oil temperature in the oil inlet tank 110 reaches the predetermined temperature, the bi-metal element 126 moves to the second position (as shown in FIG. 7, for example). In this second position, an end of the bi-metal element 126 covers an end of the bypass tube 120 thereby blocking the flow of oil through the bypass tube 120. The oil is resultantly routed through the heat exchange tubes 38 for cooling. It will be appreciated by those skilled in the art that the properties of the bi-metal element 126 may be selected in a conventional manner to attain closure of the bypass tube 120 at a particular temperature.

The heat exchanger 100 may further include a coolant valve 130 for selectively controlling the flow of coolant through the plurality of tubes 26. The coolant valve 130 may be automatically responsive to a predetermined condition for blocking the flow of coolant through the tubes 26. The coolant valve may be operative in a closed condition and an open condition. The closed condition or position is shown in FIG. 6, for example. The open condition or position is shown in FIG. 8, for example. In the open position, the coolant valve 130 allows coolant to flow through the tubes 26 for cooling. In the closed condition, the coolant valve 130 routes coolant directly back to the engine.

The predetermined condition which control opening and closing of the coolant valve 130 may be a predetermined temperature of the coolant at the coolant valve 130. For example, the means for automatically controlling the coolant valve 130 may be responsive to block an inlet to the tank 104. This predetermined temperature may be approximately 160 degrees Fahrenheit or any other identified temperature.

The means for controlling the coolant valve 130 may include a temperature-responsive valve 130. The temperature-responsive valve 130 may include an element 132 movable between a first position and a second position in response to a change in temperature. The first position of the element 132 is shown in FIG. 6. In this first position, the coolant valve 130 is closed and the element 132 precludes coolant from entering the tank 104. As a result, the coolant is returned to the engine. The second position is shown in FIG. 8. In this second position, the coolant valve is open and coolant is allowed to enter the tank 140 and thereafter pass through the tubes 26 for cooling.

The element 132 of the coolant valve 130 may be a bi-metal element 132. The bi-metal element 132 may be a wound strip. The bi-metal element 132 is operatively coupled to a rotary valve 134. A free end of the bi-metal element 132 may be moveable relative to an opening so as to provide selective flow of coolant therethrough. One suitable valve arrangement including a bi-metal element having a wound strip is shown in commonly owned U.S. Publication No. 2007/0267510, which is hereby incorporated by reference as if fully set forth herein. It will be understood by those skilled in the art that various other bi-metal elements may be incorporated within the scope of the present teachings, including but not limited to the other forms shown and described in U.S. Publication No. 2007/0267510.

When the coolant temperature at the coolant valve 130 reaches the predetermined temperature, the bi-metal element 132 moves to the second position (as shown in FIG. 8, for example). In this second position, the bi-metal element 132 allows flow to the tank 140, thereby preventing an excessive pressure buildup. When the coolant temperature at the coolant valve 130 drops below the predetermined temperature, the bi-metal element 132 moves to the first position (as shown in FIG. 6, for example). The coolant is resultantly routed back to the engine without cooling. It will be appreciated by those skilled in the art that the properties of the bi-metal element 132 may be selected in a conventional manner to attain opening and closing of the coolant valve at a particular temperature.

Turning to FIGS. 9 through 12, another heat exchanger in accordance with the present teachings is illustrated and generally identified at reference character 200. The heat exchanger 200 is similar to the heat exchanger 100 described above. The heat exchanger 200 primarily differs from the heat exchanger 100 in that it incorporates electronically-controlled valves for controlling the flow of coolant and the flow of oil. Otherwise, it will be understood that the construction and operation of the heat exchangers 100 and 200 are substantially identical. Given the similarities between the two embodiments, like reference characters will be used to identify similar elements.

The oil inlet tank 110 may incorporate an electronically-controlled valve 150 for controlling the flow of oil through the bypass tube 120. The electronically-controlled oil valve 150 may have an electric actuator 152 that is conventionally controlled by the vehicle's electronic control unit (ECU). The electronically-controlled oil valve 150 may further include a plunger 154 or other mechanism for selectively blocking flow of oil through the bypass valve 120.

The valve 150 may be operative in a first mode or open mode and a second mode or closed mode. In the first mode, shown for example in FIG. 9, the plunger may be spaced from an end of the bypass tube 120 and oil may be allowed to pass through the bypass tube 120. In the second mode, shown for example in FIG. 12, the plunger may abut the end of the bypass tube 120 and thereby prevent oil from passing through the bypass tube 120. The valve 150 is controlled by the ECU to operative in the open position in cold oil conditions. As such incoming cold oil coming from the transmission is permitted to enter the radiator for circulation purposes through the bypass tube 120, preventing an excessive pressure buildup.

The tank 104 may incorporate an electronically-controlled coolant valve 160 for controlling the flow of coolant through the tubes 26. The electronically-controlled coolant valve 160 may have an electric actuator 162 that is conventionally controlled by the vehicle's ECU. The electronically-controlled coolant valve 160 may further include a plunger 164 or other conventional mechanism for selectively blocking flow of coolant to the tank 104.

The valve 160 may be operative in a first mode or open mode and a second mode or closed mode. The coolant valve may be operative in a closed condition and an open condition. The closed condition or position is shown in FIG. 10, for example. The open condition or position is shown in FIG. 11, for example. In the open position, the coolant valve 160 allows coolant to flow through the tubes 26 for cooling. In the closed condition, the coolant valve 160 routes coolant directly back to the engine.

Turning finally to FIGS. 13 through 17, another heat exchanger in accordance with the present teachings is illustrated and generally identified at reference character 300. The heat exchanger 300 is similar to the heat exchanger 200 described above. The heat exchanger 300 primarily differs from the heat exchanger 200 in that it incorporates wax controlled valves for controlling the flow of coolant and the flow of oil. Otherwise, it will be understood that the construction and operation of the heat exchangers 200 and 300 are substantially identical. Given the similarities between the two embodiments, like reference characters will be used to identify similar elements.

The oil inlet tank 110 may incorporate a wax controlled valve 302 for controlling the flow of oil through the bypass tube 120. The wax controlled oil valve 302 may operate in a conventional manner to extend a plunger 154 in response to a predetermined temperature. In this regard, the predetermined temperature may heat the wax of the wax controlled valve 302 to extend the plunger 154 or other mechanism for selectively blocking flow of oil through the bypass valve 120.

The valve 302 may be operative in a first mode or open mode and a second mode or closed mode. In the first mode, shown for example in FIG. 13, the plunger 154 may be spaced from an end of the bypass tube 120 and oil may be allowed to pass through the bypass tube 120. In the second mode, shown for example in FIG. 15, the plunger may abut the end of the bypass tube 120 and thereby prevent oil from passing through the bypass tube 120. The valve 302 is responsive to a predetermined temperature such that the valve is open below the predetermined temperature and the valve closes at or above the predetermined temperature. As such incoming cold oil coming from the transmission is permitted to enter the radiator for circulation purposes through the bypass tube 120, preventing an excessive pressure buildup.

The tank 104 may incorporate a wax controlled coolant valve 310 for controlling the flow of coolant through the tubes 26. The wax controlled coolant valve 310 may be automatically responsive to a predetermined temperature.

The valve 310 may be operative in a first mode or open mode and a second mode or closed mode. The coolant valve may be operative in a closed condition and an open condition. The closed condition or position is shown in FIG. 10, for example. The open condition or position is shown in FIG. 11, for example. In the open position, the coolant valve 310 allows coolant to flow through the tubes 26 for cooling. In the closed condition, the coolant valve 310 routes coolant directly back to the engine.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the invention, and all such modifications are intended to be included within the scope of the invention. 

1. A heat exchanger for an internal combustion engine of a motor, the heat exchanger comprising: a first radiator tank including a plurality of walls, brazed joints between the plurality of walls to make the first radiator tank liquid tight; a second radiator tank; a plurality of radiator tubes extending between the first and second radiator tanks, brazed joints between the plurality of radiator tubes and the first and second radiator tanks; and an oil cooling structure disposed inside the first radiator tank, wherein the brazed joints between the plurality of walls and between the plurality of radiator tubes and the first and second radiator tanks are simultaneously formed. 2-34. (canceled) 